no such file to load -- mkmf
jcop@mental:~$ sudo gem install insurance Attempting local installation of 'insurance' Local gem file not found: insurance*.gem Attempting remote installation of 'insurance' Updating Gem source index for: http://gems.rubyforge.org Building native extensions. This could take a while... extconf.rb:1:in `require': no such file to load -- mkmf (LoadError) from extconf.rb:1
Thankfully, Google led me to the answer on RubyForge. For some reason, mkmf.rb is part of the ruby1.8-dev package, and initially I hadn’t installed that since it is described as
Header files for compiling extension modules for the Ruby 1.8
Ah well. A quick
sudo apt-get install ruby1.8-dev
and everything trotted along happily after that.